System and method for discriminating a roll in a paper roll dispenser, and a paper roll

ABSTRACT

The invention comprises a system and a method for discriminating a roll placed in a paper roll dispenser, as well as a paper roll with a core comprising at least one passive element having an electrical conductivity different from that of the core, to be used in conjunction with the dispenser. The system comprises at least two conducting plates located within the paper roll dispenser such that when the roll is positioned within the dispenser, the plates are in proximity of the roll, the plates being electrically insulated from each other, means for detecting capacitance between the plates and generating a signal indicative of said capacitance and means for discriminatng said paper roll based on a value of the signal.

FIELD OF THE INVENTION

The present invention generally relates to paper roll dispensers, forexample for paper towels or toilet paper. More precisely, the inventionrelates to a system and a method for discriminating a roll in a paperroll dispenser, and a paper roll.

BACKGROUND OF THE INVENTION

Several types of paper roll dispensers exist in the prior art. Thesesystem provide gradually to a user of the dispenser different types ofpaper rolled around an inner core (hereinafter referred to as a “paperroll”). The most common of these dispensers dispense paper items such aspaper towels and toilet paper. These dispensers are often used in publicarea washrooms.

An example of such a dispenser can be found in U.S. Pat. No. 6,293,486(BYRD et al.). This document describes a dispenser comprising anelectronic system, which includes a network of at least one photovoltaiccell which feeds a control circuit, which, in turn, controls overalloperation of the dispenser. The control circuit reacts to a detectiondevice, which detects variations in light. The detection of a variationin the light activates the distribution of a certain quantity of papertowels when an object, such as the hand of a user, passes in front ofthe detection device.

U.S. Pat. No. 6,412,679 (FORMON et al.) is also known in the art andteaches a motorised dispenser which can distributed individual papertowel segments from a paper roll. The dispenser comprises a controldevice capable of detecting the presence of a user, which activates thepaper feeding device. The control device is also used to control theamount of paper dispensed by preventing distribution of paper if acertain portion of paper did not detach itself properly from the roll.

U.S. patent application Ser. No. 2002/0096028 (MORAND) is also known inthe art and describes a paper towel distribution apparatus comprising apaper roll support for the paper towels and a cutting device pivotallymounted on an external peripheral part of the paper roll. The cuttingdevice can be placed between an initial position where the sharp side ofthe cutting device is positioned in proximity of the external peripheralpart, and a second position where the sharp side of the cutting deviceis moved away from the paper roll support. In this second position, thesharp side of the cutting device is positioned in a direction generallyopposite with respect to the paper roll support rotational direction,such that any pulling force exerted by a user on the paper toweldistribution system will act against the sharp side of the cuttingdevice, thereby cutting a segment of paper towel from the roll.

European patent application EP 1 232 715 discloses a paper toweldispenser which has a capacitance-charge-based proximity sensor. Theproximity detector senses when a hand is placed near the dispenser, andthereupon dispenses a set amount of towel. The proximity sensorcomprises a circuit according to a balanced bridge principle whereindetection is based on detecting a phase difference, which depends uponthe amount of detected capacitance difference or change.

Other systems in the prior art relate to paper roll anti-theftprotection devices. U.S. Pat. No. 6,653,940 teaches a method and systemfor preventing the unauthorized removal of paper rolls, such as cashregister receipt paper rolls used by retailers, as well as theanti-theft paper roll and methods of preparation therefor. The methodcomprises affixing to the paper roll an electronic sensor, wherein thesensor emits a detectable signal and detecting the presence of thesensor when it passes through or near a detection point at the retailerslocation. In one embodiment of the invention, the sensor is an adhesivestrip, affixed to the core of the paper roll, wherein the core of thepaper roll comprises a flat surface integrally formed therein, ontowhich the sensor is affixed.

Of course, several other documents describe generally paper dispensersand these documents are known to the Applicant by the following U.S.application and/or patent numbers: U.S. 2002/0019971 A1 (LEWIS et al.);U.S. 2002/0113109 A1 (GRACYALNY et al.); U.S. 2001/0032858 A1 (KAPILOFF,et al.); U.S. Pat. Nos. 6,439,502 B1 (GEMMEL et al.); 5,868,275 (MOODY,et al.); 5,820,231 (SCHÖN); 5,803,373 (SEDLOCK, JR. et al.); 5,452,832(NIADA); 5,375,920 (MACCHI CASSIA); 5,375,785 (BOONE et al.); 5,294,192(OMDOLL et al.); 4,807,824 (GAINS et al.); 4,738,176 (CASSIA, et al.);and 3,948,715 (TOKUNO).

As shown above, certain prior art dispensers allow a distribution ofpaper towels through light detection systems, motion detectors and/orcapacitance-change-based proximity sensors capable of detecting thepresence of a user near the dispenser.

However, it would be advantageous for several different reasons, notablyfor reasons of quality control and a reduction of maintenance and repaircosts for dispensers, to develop a paper roll dispenser which can onlyoperate with paper rolls specifically tailored for use in the dispenser.Thus, there is presently a need for a type of dispenser which can reducethe occurrences of damages caused to the dispenser through installationof an improper roll in the dispenser.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a system and amethod for discriminating a roll in a paper roll dispenser.

It is also an object of the present invention to provide a paper rollwhich can be discriminated.

According to the present invention, there is provided a system fordiscriminating a roll placed in a paper roll dispenser, comprising:

-   -   at least two conducting plates located within the paper roll        dispenser such that when the roll is positioned within the        dispenser, the plates are in proximity of the roll, the plates        being electrically insulated from each other;    -   means for detecting capacitance between the plates and        generating a signal indicative of the capacitance; and    -   means for discriminating said paper roll based on a value of the        signal.

According to the present invention, there is also provided a method fordiscriminating a roll placed in a paper roll dispenser comprising thesteps of:

-   -   a) placing the roll in the dispenser;    -   b) providing at least two conducting plates located within the        paper roll dispenser such that when the roll is positioned        within the dispenser, the plates are in proximity of the roll,        the plates being electrically insulated from each other;    -   c) detecting capacitance between the plates;    -   d) generating a signal indicative of said capacitance; and    -   e) discriminating said paper roll based on a value of the        signal.

According to the present invention, there is also provided a paper rollcomprising a core comprising at least one passive element having anelectrical conductivity different from that of the core.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention and its advantages will be more easily understoodafter reading the following non-restrictive description of preferredembodiments thereof, made with reference to the following drawings inwhich:

FIG. 1 is a perspective view of a dispenser which includes a system fordiscriminating a roll according to a preferred embodiment of theinvention showing the paper roll inserted in the dispenser;

FIG. 2 shows a schematic perspective view of a paper roll according to apreferred embodiment of the present invention;

FIG. 3 shows a partial perspective view of parts of the system accordingto the present invention, in relation with parts of the dispenser;

FIG. 4 shows a side view of what is shown in FIG. 3;

FIG. 5 shows a front view of what is shown in FIGS. 3 and 4;

FIG. 6 shows a perspective view of the components of the according tothe present invention;

FIG. 7 shows a schematic block diagram of components of the systemaccording to the present invention;

FIG. 8 shows a schematic representation illustrating the relationbetween the plates according to the present invention and a paper roll;

FIG. 9 shows a schematic representation illustrating the relationbetween the plates according to the present invention and a paper rollaccording to the present invention; and

FIG. 10 shows a graph illustrating voltages applied to the conducting inrelation to different paper rolls, versus time.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

As aforesaid and shown in FIGS. 1 and 7, it is an object of the presentinvention to provide a system and a method for discriminating a roll 12in a paper roll dispenser 14. The system for discriminating a roll 12placed in a paper roll dispenser 14, comprises at least two conductingplates 20 located within the paper roll dispenser 14 such that when theroll 12 is positioned within the dispenser 14, the plates 20 are inproximity of the roll 12. The plates 20 are electrically insulated fromeach other. The system further comprises means for detecting capacitancebetween the plates and generating a signal indicative of saidcapacitance and means for discriminating the paper roll based on a valueof the signal. The plates 20 are in proximity of the roll 12 in that ifthe roll comprises an element having an electrical conductivity fromthat of the paper roll core, the capacitance measured between the plates20 is affected.

Preferably, as shown in FIGS. 3 to 6, the at least two, and preferablyfour, conducting plates 20 are shaped and positioned in an annularfashion in proximity of a roll support structure 22 within the dispenser14.

Preferably, capacitance is detected between an individual pair ofadjacent plates 20 in a sequenced manner one pair after another suchthat all combinations of capacitance between adjacent conducting plates20 are detected.

In accordance with a preferred embodiment and as shown in FIG. 7, themeans for detecting capacitance comprises means for applying voltagebetween two adjacent plates 20. Preferably, the means for applyingvoltage is included in an oscillator 26 operating at 4 KHz. The meansfor detecting capacitance also comprises means for measuring voltagebetween two adjacent plates 20. Preferably, the means for measuringvoltage is included in a microprocessor 28 operating at 1 MHz. The meansfor detecting capacitance also comprises control means for controllingthe means for applying and the means for measuring, in order to scaneach pair of plates 20 by sequentially applying the voltage between theplates 20 of the pair during a given time period, and either measuringthe charge or discharge rate of voltage between the plates 20 of thepair, said charge or discharge rate being indicative of the capacitance.Preferably, the control means is included in a microprocessor 28.

Preferably, the means for discriminating said paper roll comprisescomparing means which compares the signal resulting from the charge andthe discharge of the conducting plates to a reference signal.Preferably, the comparing means is included in a microprocessor 28 asshown in FIG. 7.

Preferably, the system according to the present invention furthercomprises means for compensating the signal resulting from the chargeand the discharge of the conducting plates for changes in an environmentsurrounding the system. Preferably, the means the compensating isincluded in a microprocessor 28 as shown in FIG. 7.

Preferably, the system according to the present invention furthercomprises means for detecting a placement of the roll in the system.Preferably, the means for detecting are detection switches 30 a and 30 bas shown in FIG. 7.

Preferably, the system according to the present invention furthercomprises means for informing a user of results of an assessment made bythe means for discriminating. Preferably, the means for informing theuser comprises a green light 32 a and a red light 32 b, either one beingactivated depending on the results of the assessment made by the meansfor discriminating, as shown in FIG. 7.

Preferably, the system according to the present invention furthercomprises means for converting the charge or discharge rate of voltageinto a continuous voltage. Preferably, the means for converting islocated between the means for applying the voltage and the means formeasuring the voltage, such as between the oscillator 26 andmicroprocessor 28 shown in FIG. 7.

Preferably, the system further comprises at least one battery 34 toprovide power to the system, a paper level switch 36 to indicate to thesystem the amount of paper left on the roll 12, and a printed circuitboard 38 as shown on FIGS. 3 to 6.

As aforesaid and shown in FIG. 2, it is also an object of the presentinvention to provide a paper roll 12 which can be discriminated.

As shown in FIG. 2 and according to the present invention, the paperroll 12 comprises a core 50 comprising at least one passive element 52having an electrical conductivity different from that of the core 50.

Preferably, the core 50 has a hollow cylindrical shape and comprises atleast two strips of material, preferably cardboard helicoidally rolledaround a central axis.

Preferably, the at least one passive element 52 is placed at aninterface between the at least two strips of material. Because thestrips are helicoidally rolled, the at least one passive element 52 willalso have a corresponding spiral shape.

In another preferred embodiment, the core 50 can comprise more than onepassive element 52. Preferably, the passive elements 52 are placedsymmetrically around the central axis of the roll 12 such that, at anypoint along the central axis of the roll 12, there is an equal angulardistance with respect to the central axis between passive elements 52along a circumference of the roll 12 (e.g. 120 degrees between 3elements, 180 degrees between two elements).

Preferably, the system according to the present invention comprises oneadditional conductive plate 20 compared to the number of passiveelements 52 in the core 50 of the roll 12 to be discriminated. Forexample, if the core 50 comprises three passive elements 52, the systemshould comprise four conductive plates 20. Consequently, given thesymmetry in the placement of the passive elements 52, detection of achange in the capacitance between the plates will occur between threepairs of plates out of the possible four pairs of plates. By having morethan one passive element in the paper roll core, it is possible tofurther characterize the roll in question.

Preferably, the at least one passive element 52 is a copper wire and is36 AWG in size. This material and size are chosen for manufacturingconsideration, since this type of wire is easily cut by the saw whichalso cuts the strips that eventually form the core.

The basic principle behind the detection of the passive element 52 inthe core 50 is the measurement of a change in capacitance. In apreferred embodiment of the present invention, the change in capacitancebetween a core having a passive element and a core not having a passiveelement is of the order of 0.3 pF. Preferably, the detection systemcomprises four conducting plates 20 shaped and positioned in an annularfashion in proximity of a roll support structure 22 within the dispenser14. When the means for detecting a placement of the roll in the system30 a and 30 b is activated after an actual placement of a roll in thesystem, the system is activated and measurements of capacitance betweenadjacent conductive plates 20 are taken. The conductivity of the passiveelement 52 in the core will have an effect of modifying the frequency ofthe oscillator 26 connected to the different plates 20 a, 20 b, 20 c and20 d as shown in FIG. 7. One after the other, the microprocessor 28 willconnect the oscillator 26 with the different plates 20 a, 20 b, 20 c and20 d and will store in its memory the obtained frequency and willautomatically compensate for any changes in the environment of thesystem. In this manner, the microprocessor 28 is able to clearlyidentify the model of the paper roll product inserted into the dispenser14. If the inserted paper roll 12 corresponds to the desired model ortype of product, a green light 32 a will be activated to indicate thevalidity of the product. Otherwise, a red light 32 b will be activatedto indicate that the inserted paper roll does not correspond to thedesired model.

Hence one element of novelty of the present invention resides in theinsertion in the core 50 of the paper roll 12 of a passive element 52having an electrical conductivity different from that of the cardboardused during manufacturing of the core 50. This passive element 52constitutes a distinctive feature which allows its detection andidentification of the model of the paper roll.

When the paper roll 12 is inserted in the dispenser 14, the systemaccording to the present invention validates the number of distinctiveelements present in the core 50 of the paper roll 12 and can thenactivate or not a locking system for the paper roll 12.

When the model of the paper roll 12 is considered to be valid, thesystem will transition to an energy-saving mode, and no other apparentevent will occur except for the activation during a short amount of timeof the green light 32 a to indicate the validity of the paper roll 12.

Otherwise, the system can command means 40 so that the dispenser cannotbe used. During this operation, a red light 32 b will indicate during ashort amount of time the non-conformity of the paper roll 12.

In either case, whatever the type of paper roll 12 inserted in thedispenser 14, the system will be activated and detect the nature of thepaper roll 12 upon sensing the insertion of a paper roll 12 on the rollsupport structure 22 in the dispenser 14.

The measurement of the change of capacitance is based on the principleof accumulation of energy between two conductive surfaces separated byan insulating material. When voltage is applied to two plates 20,electrical charges are blocked by the insulating material between theplates 20 and accumulate, thereby creating a voltage difference.

As shown in FIG. 8, the more the insulating material has betterinsulating properties, the less charges can be transferred from oneplate 20 a to another plate 20 b and passage of charges 60 between theplates individually connected to the oscillator 26 is hindered.Consequently, a voltage difference between the plates 20 can increasemore rapidly since there is no loss of charges 60 between the plates 20which are inserted around the plastic roll support structure 22.

As shown in FIG. 9, by inserting a passive element 52 having anelectrical conductivity different from that of the paper roll core 50 inFIG. 8, the insulating properties of the insulating material between thetwo conductive plates 20 is affected. In a preferred embodiment of thepresent invention, this passive element 52 is a copper wire. Hence, whena conducting material like the copper wire is in proximity of the twoplates, the passive element 52 creates a path facilitating the passageof charges 60 from one plate to the other. This has the result ofreducing the insulating properties of the material between the platesand therefore facilitates the passage of electrons. Consequently, thevoltage difference developed between the plates increases more slowly,in a situation analogous to attempting to fill a bucket with watercompared to attempting to fill a bucket with water when there is a holein the bucket.

According to a preferred embodiment of the present invention, the systemcomprises an oscillator 26 which applies a voltage to the conductingplates 20. The plates will be charged in a manner dependant on thequality of the insulating material which will be affected by thepresence or not of the passive element 52 in the paper roll core 50. Asshown in FIG. 10, when the voltage difference between the plates reachesa particular target level 64, the oscillator 26 reverses itself anddischarges the energy accumulated between the plates 20. The better theinsulating properties of the material 66, the more rapidly the targetvoltage level 64 is reached, and therefore the oscillatory action of theoscillator is quicker. When the passive element 52 is present 68, theloss of charges from one plate to the other is greater, hence the timerequired for charging the plates and reaching the target level voltagedifference is increased, resulting in a lower frequency. In FIG. 10, thetarget voltage level 64 is set to 100% of the voltage supplied to thesystem. In a preferred embodiment of the present invention, in order toreduce power consumption by the system, the target voltage level is setat a lower percentage of the voltage supplied to the system, e.g. 50%.

Preferably, an electronic component is inserted between the oscillator26 and the microprocessor 28 to convert the frequency into a constantvoltage. The level of this voltage is a function of the frequency. Ifthe frequency increases, the voltage will increase accordingly.Preferably, the electronic component comprises a low-pass filter havinga cutoff frequency at 16 Hz.

As disclosed hereinabove in the Summary of the Invention, it is also anobject of the present invention to provide a method for discriminating aroll in a paper roll dispenser, involving five basic steps to which maybe added a plurality of optional steps.

The method for discriminating a roll in a paper roll dispenser ispreferably carried out using the following sequence of steps:

-   -   a) placing the roll in the dispenser;    -   b) providing at least two conducting plates located within the        paper roll dispenser such that when the roll is positioned        within the dispenser, the plates are in proximity of the roll,        the plates being electrically insulated from each other;    -   c) detecting capacitance between the plates;    -   d) generating a signal indicative of said capacitance; and    -   e) discriminating said paper roll based on a value of the        signal.

Preferably, the method further comprises the steps of:

-   -   detecting a placement of the roll in the system after step a)        and before step c); and    -   initiating step c) upon detection of the placement of the roll        in the system.

The method for discriminating a roll in a paper roll dispenser is alsopreferably carried out using the following more detailed sequence ofsteps, wherein:

-   -   step b) comprises the step of providing at least two conducting        plates shaped and positioned in an annular fashion in proximity        of a roll support structure within the dispenser;    -   step c) comprises the steps of        -   applying voltage between two adjacent plates of said plates;            and        -   measuring voltage between two adjacent plates of said            plates;    -   step d) comprises the steps of        -   scanning each pair of said plates by sequentially applying            the voltage between the plates of the pair during a given            time period, and either measuring the charge or discharge            rate of voltage between the plates of the pair to produce            said signal; and        -   compensating said signal for changes in an environment            surrounding the system;    -   and    -   step e) comprises the steps of        -   comparing said signal to a reference signal to obtain an            assessment of the signal;        -   converting said assessment signal into a continuous voltage;            and        -   informing a user of results based on the continuous voltage.

Although the present invention has been explained hereinabove by way ofa preferred embodiment thereof, it should be pointed out that anymodifications to this preferred embodiment within the scope of theappended claims is not deemed to alter or change the nature and scope ofthe present invention.

1. A system for discriminating a roll placed in a paper roll dispenser,comprising: at least two conducting plates located within the paper rolldispenser such that when the roll is positioned within the dispenser,the plates are in proximity of the roll, the plates being electricallyinsulated from each other; means for detecting capacitance between theplates and generating a signal indicative of said capacitance; and meansfor discriminating said paper roll based on a value of the signal. 2.The system of claim 1, wherein the at least two conducting plates areshaped and positioned in an annular fashion in proximity of a rollsupport structure within the dispenser.
 3. The system of claim 2,wherein the means for detecting detects the capacitance between anindividual pair of adjacent plates of said plates in a sequenced mannerone pair after another such that all combinations of capacitance betweenadjacent conducting plates are detected.
 4. The system of claim 1,wherein the means for detecting comprises: means for applying voltagebetween two adjacent plates of said plates; means for measuring voltagebetween two adjacent plates of said plates; control means forcontrolling said means for applying and means for measuring to scan eachpair of said plates by sequentially applying the voltage between theplates of the pair during a given time period, and either measuring thecharge or discharge rate of voltage between the plates of the pair toproduce said signal.
 5. The system of claim 4, wherein the means forapplying voltage is an oscillator.
 6. The system of claim 4, wherein themeans for measuring voltage is integrated in a microprocessor.
 7. Thesystem of claim 6, wherein the control means is integrated in themicroprocessor.
 8. The system of claim 1, wherein the means fordiscriminating said paper roll comprises comparing means which comparesthe value of said signal to a reference signal.
 9. The system of claim8, wherein the comparing means is a microprocessor.
 10. The system ofclaim 1, further comprising means for compensating said signal forchanges in an environment surrounding the system.
 11. The system ofclaim 10, wherein the means for compensating is integrated in amicroprocessor.
 12. The system of claim 1, comprising means fordetecting a placement of the roll in the system.
 13. The system of claim1, comprising means for informing a user of results of an assessmentmade by the means for discriminating.
 14. The system of claim 13,wherein the means for informing the user comprises a green light and ared light, either one being activated depending on the results of theassessment made by the means for discriminating.
 15. The system of claim4, further comprising means for converting said signal into a continuousvoltage.
 16. A method for discriminating a roll placed in a paper rolldispenser comprising the steps of: a) placing the roll in the dispenser;b) providing at least two conducting plates located within the paperroll dispenser such that when the roll is positioned within thedispenser, the plates are in proximity of the roll, the plates beingelectrically insulated from each other; c) detecting capacitance betweenthe plates; d) generating a signal indicative of said capacitance; ande) discriminating said paper roll based on a value of the signal
 17. Themethod of claim 16 further comprising the steps of: detecting aplacement of the roll in the system after step a) and before step c);and initiating step c) upon detection of the placement of the roll inthe system.
 18. The method of claim 16, wherein: step b) comprises thestep of providing at least two conducting plates shaped and positionedin an annular fashion in proximity of a roll support structure within thdispenser; step c) comprises the steps of applying voltage between twoadjacent plates of said plates; and measuring voltage between twoadjacent plates of said plates; step d) comprises the steps of scanningeach pair of said plates by sequentially applying the voltage betweenthe plates of the pair during a give time period, and either measuringthe charge or discharge rate of voltage between the plates of the pairto produce said signal; and compensating said signal for changes in anenvironment surrounding the system; and step e) comprises the steps ofcomparing said signal to a reference signal to obtain an assessment ofthe signal; converting said assessment signal into a continuous voltage;and informing a user of results based on the continuous voltage.
 19. Apaper roll comprising a core having at least one passive element havingan electrical conductivity different from that of the core.
 20. Thepaper roll of claim 19, wherein the core has a hollow cylindrical shapeand comprises at least two strips of material helicoidally rolled arounda central axis.
 21. The paper roll of claim 20, wherein the at least onepassive element is placed at an interface between the at least twostrips of material.
 22. The paper roll of claim 20, wherein the corecomprises more than one passive element and the passive elements areplaced symmetrically around the central axis of the roll such that, atany point along the central axis of the roll, there is an equal angulardistance with respect to the central axis between passive elements alonga circumference of the roll.
 23. The paper roll of claim 19, wherein theat least one passive element is a copper wire.
 24. The paper roll ofclaim 23, wherein the copper wire is 36 AWG in size.